Anybody know where this happened at? I noticed in the first post the link to the pic had something about "found at Abilene Clay Sports" I shoot there quite often but don't remember this particular incident.

We now know who it belonged to. He sustained a small cut to one finger and nothing else except maybe a sore shoulder. Apparently a 28 ga shell was dropped in and not noticed, then a 20 ga was put in on top of the 28, more commonly called a 20/28 burst. The pictures are not clear enough to see all this evidence, however, there are indications of another shell being lodged in the forcing cone area. The buttstock was also shattered and split clear back into the comb area. We at Abilene Clay Sports are thankful that there was no serious injury, as it was very possible. We are framing it in a shadow box to hang on the wall as a SAFETY reminder to all

If a 20-gauge shell lodged in the barrel of a 12-gauge gun was not the explosion threat that it is, the ammunition industry would not have adopted yellow as THE color for 20-gauge shells and none other. You want to try shooting your 12-gauge with a 20 in the barrel? Let us know how that works out for you.

I have a near new Beretta 682 Optima Over and Under barrel that had a 20/12 accident. It damn near removed the shooters left thumb. It also spread the receiver. Those barrels ar proofed at 15,000 psi. You won't convince me that a over loaded shell will do that. You can build more pressure with increasing the shot charge then powder. But that is not as much pressure as you will get with 2 shells burning at the same time and one of them not contained in a chamber.